HDR photos are used to capture scenes having a large dynamic range. However, using more number of photos can lead to unwanted artifacts from poor alignment or ghosting. For optimal HDR merge, the aim is to capture photos in a manner that each part of the scene is well-exposed, that is neither blown-out nor under-exposed in at least one of the photos.
- If your HDR bracketing is less than 3.0 stops in total separation (-1.5, 0, +1.5), use only the darkest and brightest exposures to generate an HDR. Capturing the middle exposure, or zero exposure, is not necessary for generating a quality exposure blend in such cases. If you exceed the 3-stop separation between the darkest and the brightest exposures, an additional exposure offset becomes necessary to process a good quality HDR photo.
- If you are a photographer using the ± 1.5 exposure bracket, you can ignore the zero or middle exposure. This helps in faster render and improves alignment odds in the resultant HDR by reducing the chances of potential camera movement between the exposures. However, the zero exposure can be useful in scenarios where the capture scene is within the acceptable range of a single exposure and can be developed independently.
- If you are a standard HDR shooter using a ± 2.0 bracket, you ideally require only three photos to merge into an HDR.
- If you are a 5 shot ± 4.0 stop shooter, you can now drop from 5 shots to 4 shots for merging and processing HDR. However, if you are a 7 shot ± 6.0 stop shooter, you can now get the optimal HDR blend with only 5 shots (-6.0, –3.0, 0, 3.0, 6.0) provided your camera has three-stop stepping in the exposure bracketing function.
In the HDR Merge Preview dialog, deselect the Auto Align and Auto Tone options, if necessary.
- Auto Tone: Provides a good starting point for an evenly-toned merged image
- Auto Align: Useful if the images being merged have slight movement from shot to shot. Enable this option if the images were shot using a handheld camera. Enabling this option may not be necessary if the images were shot using a tripod.
Sometimes, after the exposure-bracketed images are merged, some areas in the HDR image may appear unnaturally semi-transparent. Select one of the following deghosting option in the HDR Merge Preview dialog box to correct these anomalies: None, Low, Medium, or High. Try Low deghosting first to obtain a clean merged image. Try higher settings if necessary. Avoid using if your preview is free of ghosting artifacts.
- Low: Cures little or minor movement between frames
- Medium: Cures considerable movement between frames
- High: Cures high movement between frames
To group the exposure-bracketed images and the HDR image in to a stack (after the images are merged), select the Create Stack option. The merged HDR image will be displayed at the top of the stack.
The Create Stack options has been introduced in Lightroom Classic CC 7.4 (April 2018 release)